Parkinson's - MDS-UPDRS and PDQ-39

What is Parkinson's disease? 

A progressive neurodegenerative disorder characterised by clinically by motor symptoms (tremor, rigidity, bradykinesia) caused by loss of dopaminergic neurons in the substantia nigra.

What are symptoms of Parkinson's?

Tremor, rigidity, Postural disturbance, bradykinesis, constipation, speech, panic attacks, loss of smell, sweating, dementia etc. 

How is PD diagnosed? 

Clinical diagnosis, based on motor features, patient story and response to medication. Supported by but not dependent on imaging or biomarkers.

What are pharmacological treatments for PD? 

Levodopa, dopamine agonists, MAO-B inhibitors, COMT inhibitors, amantadine, duodopa/apomorphine. 

What are other treatments for PD? 

Deep brain stimulation (DBS) non drug therapies, exercise, neurophysiotherapy, speech and language therapy, counselling/psychological interventions.

What is a standardised assessment? 

Structured tool used to measure specific clinical or psychological constructs. Administered and scored in a consistent and reproducible manner. Typically supported by pscyhometric validation.

What are key psychometric properties? 

Reliability – consistency of measurement. Validity – measures what it intends to measure. Sensitivity to change – detects clinically meaningful changes. Feasibility – practicality in clinical or research settings. 

Why do we need standardised assessments? 

PD presents with heterogeneous motor and non-motor symptoms. Clinical presentation varies across individuals and disease stages. Standardised assessments allow: measurement of symptoms, monitoring of disease progression, evaluation of treatment effectiveness comparison across patients and studies, communication within multidisciplinary teams.

What are PD clinician-rated measures?

Assess observable signs and clinical severity. Example: MDS-UPDRS.

What are PD patient reported outcome measures (PROMs)? 

Capture the patient’s perspective and lived experience. Example: PDQ-39. 

What are PD staging and functional measures? 

Provide a global overview of disease severity. Examples: hoehn and yahr scale. Schwab and England ADL scale. 

How are standardised assessments used? 

Clinical practice, research and clinical trials and service evaluation

How is clinical practice used?

Monitor symptom progression, guide treatment decisions, evaluate response to medication or surgery e.g DBS 

How are research and clinical trails used?

Primary and secondary outcomes measured, standardised comparison across studies, regulatory approval of new therapies.

How is service evaluation used?

Assess quality of care and inform healthcare planning and policy

What does MDS-UPDRS mean? 

Movement disorder society – unified PD rating scale 

What is the MDS-UPDRS?

Gold-standard assessment of disease severity. Revision of the original UPDRS to improve reliability and validity. Used extensively in clinical practice and research. Must complete training and receive certificate before being able to administer. 

What is the structure of the MDS-UPDRS?

Part 1 – non motor experience of daily living (clinician delivered, patient self-report), part 2 motor experiences of daily living (patient self-report), motor examination (clinician-rated), motor complications (clinician delivered, patient self-report).

How are the answers scored? 

Each item scored on a 0-4 ordinal scale. 0= normal, 4 = severe impairment. Higher scores indicate greater severity. Scores can be analysed by individual parts or as a total score. Assessments often conducted in ON and OFF medication states.

What are strengths of the MDS-UPDRS?

Comprehensive assessment of motor and non-motor symptoms. Strong reliability, strong validity. Test-retest: ICCs > .90 for all subscales. Sensitive to disease progression and treatment effects. Widely used in clinical trials and practice. Facilitates standardised communication among clinicians. 

What are limitations of the MDS-UPDRS?

Symptom heterogeneity: not all people with Parkinson's experience tremor; different motor subtypes exist. Symptom fluctuations: scores may vary depending on good vs bad days and medication states. Inter-rater variability: particularly relevant for the motor examination. Time and training requirements: administration can be resource intensive. Ordinal scoring: the 0-4 scale may limit sensitivity to subtle changes.

What is the PDQ-39? 

Parkinson’s disease questionnaire with 39 items, a patient reported outcome measure. Assesses health related quality of life (HRQoL), captures the lived experience of parkinson’s disease. Widely translated and validated internationally.

What are the domains of the PDQ-39? 

Stigma, activities of daily living, bodily discomfort, cognitions, emotional wellbeing, mobility, communication and social support.

How is the PDQ-39 scored?

39 items across 8 domains, each scored 0-4. 0 =never and 4= always/cannot do at all. A domain score is formulated: (sum of domain items/maximum possible score) x 100. Scores range from 0-100 per domain; higher scores = worse QoL. PDQ-39 summary index: mean of all 8 domain scores. Provides a single overall HRQoL score. Can be used as a total score or examined domain-by-domain.

What are limitations of the PDQ-39? 

Subjective: influenced by mood, expectations and cognitive status. Ceiling and floor effects in some domains, cognitive impairment may reduce reliability of self-report. Summary index collapses meaningful domain variation into a single number, not disease specific to subtypes. Social desirability bias – underreporting of stigmatizing symptoms or less likely to respond truthfully if in presence of partner or spouse. 

What are strengths of the PDQ-39?

Captures lived experience, sensitive to changes in HRQoL overt time and following intervention, brief and self-administered (10 mins), internal consistency: chronbach’s a = .72-.95 across domains, test-retest: ICCs = .76-.93 across domains, widely used in clinical trials as a primary or secondary outcome measure, complements clinician-rated tools by adding the patient voice.